1. Field
The present invention relates to a novel protein skeletal module (scaffold protein) which increases binding affinity or binding specificity of an active polypeptide thereof, and more particularly, to a scaffold protein comprising an active polypeptide, the scaffold protein comprising: a) a polypeptide consisting of the 1st to the 19th amino acid residues of an amino acid sequence represented by SEQ ID NO: 1; b) a polypeptide including an active polypeptide; and c) a polypeptide consisting of the 29th to the 86th amino acid residues of the amino acid sequence represented by SEQ ID NO: 1, and a method for preparing the same.
2. Discussion of the Background
According to analysis on amino acid sequences and secondary and tertiary structures of proteins, many proteins are composed of independent domains or modules. The domain is a structurally and functionally independent unit. One or more of the same domains may be distributed in various proteins, and one protein may be composed of several domains. Specific information about domains can be found on websites for bioinformatics, such as Prosite (Hulo N etc., Nucleic Acids Res, 36:D245-249, 2008; Website: http://kr.expasy.org/prosite/) and SMART (Letunic I etc., Nucleic Acids Res, 34:D257-D260, 2006; Website: http://smart.embl-heidelberg.de/).
Intermolecular interactions (e.g., protein-protein interactions, protein-nucleic acid interactions, etc.) perform important functions in various life phenomena, such as growth, differentiation, and development of cells, intercellular/intracellular signaling, and mass transfer. In the related art, antibodies (full-length antibodies or their fragments) have been dominantly developed as molecules that specifically bind to target molecules to regulate their biological activities. However, antibodies have various problems such as less expression, low solubility, the use of animal cell-expressing cell lines, high costs in purification, and low stability in a reducing intracellular environment. Accordingly, non-antibody proteins that overcome the problems of antibodies and bind specifically to target molecules like the antibodies need to be urgently developed.
Peptides discovered by methods such as phage display and the like to be used for diagnosis and treatment of cancers or arteriosclerosis have limitations, such as low binding affinity, non-stability, and high immunogenicity. Accordingly, new technologies that can increase binding affinity and stability of an active peptide and decrease immunogenicity of the active peptide in vivo while overcoming such problems need to be developed.